1. Field of the Invention
The invention relates generally to double-faced display devices, and more particularly to a kind of double-faced plasma display panel.
2. Prior Art
A plasma display panel is a thin flat screen display device having a large screen size. In use, electrons are accelerated by an electric field so that the accelerated electrons collide with a discharge gas. This causes excitation of the discharge gas and subsequent remission. The remission process causes radiation of ultraviolet rays. The ultraviolet rays irradiate a fluorescent material, whereby the ultraviolet rays are converted into visible light.
FIG. 5 is an isometric view of part of a conventional plasma display panel 1. The plasma display panel 1 comprises a transparent substrate 11 and an opaque substrate 12. A plurality of scanning electrodes 14 and a plurality of displaying electrodes 13 are alternately arranged on an inner surface of the transparent substrate 11, and are each aligned in a first horizontal direction. A transparent dielectric layer 15 covers the scanning electrodes 14 and the displaying electrodes 13, so that the scanning electrodes 14 and the displaying electrodes 13 are embedded in the transparent dielectric layer 15. A protection layer 16 covers the transparent dielectric layer 15. A plurality of addressing electrodes 17 are arranged on an inner surface of the opaque substrate 12, and are each aligned in a second horizontal direction. The second horizontal direction is perpendicular to the first horizontal direction, and the inner surface of the opaque substrate 12 is opposite to the inner surface of the transparent substrate 11. An opaque dielectric layer 18 covers the addressing electrodes 17, so that the addressing electrodes 17 are embedded in the opaque dielectric layer 18. A plurality of separation walls 19 extend up from the opaque dielectric layer 18, the separation walls 19 each being aligned in the second horizontal direction. Each separation wall 19 generally separates two adjacent addressing electrodes 17. A fluorescent layer 10 is coated on exposed regions (not labeled) of the opaque dielectric layer 18 and side faces (not labeled) of the separate walls 19. The fluorescent layer 10 comprises three primary colors, such as red, green and blue. A discharge gas is filled within a discharge space 168 defined between the protection layer 16 and the opaque dielectric layer 18.
When a voltage applied between the displaying electrodes 13 and the scanning electrodes 14 is more than the starting voltage, the discharge gas in the discharge space 168 discharges and generates ultraviolet rays. The ultraviolet rays irradiate the fluorescent layer 10, and the fluorescent layer 10 luminesces in accordance with the three primary colors. Thus visible light is emitted from an outer surface of the transparent substrate 11.
U.S. Pat. No. 6,703,772 discloses a similar kind of plasma display panel. In such plasma display panel, an image is only displayed on an outer surface of the transparent substrate, and cannot be displayed on an outer surface of the opaque substrate. However, in certain applications, the plasma display panel is required to simultaneous display images at two opposite sides thereof. Generally, a pair of such plasma display panels are adopted to form a double-faced plasma display panel assembly. The opaque substrates of the plasma display panels are engaged with each other. In such kind of double-faced plasma display panel assembly, two driving systems are needed. Furthermore, the structure of the double-faced plasma display panel assembly is complicated. Thus, the double-faced plasma display panel assembly is bulky and expensive.
A double-faced plasma display panel which overcomes the above-mentioned problems is desired.